1. Field of the Invention
This invention relates to a camera, and more particularly to a camera of the type incorporating a motor for performing a charging operation on the internal mechanisms of the camera, such as a shutter, etc., and a film feeding operation.
2. Description of the Prior Art
In the conventional single-lens reflex camera, operations such as a releasing action on a film winding stop claw, a mirror returning action and an automatic stop quick returning action have been arranged to be mechanically performed after completion of the travel of the trailing shutter blade. The conventional arrangement, therefore, has necessitated the use of a much greater driving force for shutter charging than the driving force required for driving the shutter blades.
To eliminate this shortcoming of the conventional camera, there have been proposed various arrangements including: utilization of the strong spring force of a mirror driving spring, which must have a strong spring force to begin with, also for winding stop releasing, mirror returning and automatic quick returning actions; and use of a shutter that permits much reduction in the driving force thereon by virtue of a relatively small load it imposes on the motor.
However, with a shutter arranged to be controlled by such a small driving force, the shutter tends to give rise to the trouble that the shutter blades do not travel even when a driving signal is applied to the shutter, or that the shutter blades stop halfway during their travel. In the case of such a malfunction, no signal representative of completion of the travel of the trailing shutter blade is obtained. Therefore, the camera becomes incapable of proceeding to the next sequence of actions. Under such a condition, the mirror is left in a lifted up state, and the shutter in an open state. Then, an inadvertent film rewinding under that condition would ruin not only an unused portion of the film, but also a normally photographed portion thereof by unintentionally exposing the whole film to light. Besides, with the mirror left in the lifted up state, the shutter blades might be damaged by the sunlight.